During solidification of a pure metal, the radius of critical nucleus at an undercooling of 10 K is _______ x10^-9 m (answer rounded off to 1 decimal place).
Given: solid/liquid interface energy =0.177 J⋅m^-2;
melting point of the metal =1356 K and
latent heat of fusion =1.88x10⁹ J⋅m^-3